Diacavolinia limbata (d'Orbigny, 1836) forma limbata (d'Orbigny, 1836)
Shell triangular in outline, hyaline, brown-purple. Ventral side convex, without flattened area as in forma africana. Twenty-five ventral ribs, in anterior group of 15 strong ribs, and a posterior group of weak ribs. Dorsal side slightly convex, with well-developed central ribs, lateral ribs and lock ribs. Lateral lines slightly convex. Flanks not pronounced. Lock area well-developed with a large main tubercle and link. No separate lunar or minor tubercles. Second lock mechanism at upper level of attachment of spines to lateral side. Sculpture of faint growth lines and faint transverse striation. Lateral spines slightly bent, sharp, hooked; gutter corners large. Caudal spine and caudal spine mark absent. Broad dorsal lip with small notch and gutter but no constriction. Ventral lip moderately sized with well-developed median depression. No lip flaps; low and strong lip bellies and small lip shoulders. Hump absent. Protoconch II area projecting moderately, the relatively small caudal joint is about 1.36 mm, caudal fold, about 1.68 mm long, moon-shaped. Shell length: 12.7 mm, width: 10.4 mm.